This invention relates to a portable aerosol medication delivery apparatus and system for administering a desired respirable dosage of a medication in aerosol form to a patient""s lungs by oral inhalation.
The use of aerosol medication delivery systems to administer medication in aerosol form to a patient""s lungs by inhalation is well known in the art.
Conventional aerosol medication delivery systems include pressurized metered-dose inhalers (pMDIs). Conventional pMDIs typically have two components: a canister component in which the medication particles are stored under pressure in a suspension or solution form and a receptacle component used to hold and actuate the canister. The canister component typically includes a valved outlet from which the contents of the canister can be discharged. Aerosol medication is dispensed from the pMDI by applying a force on the canister component to push it into the receptacle component thereby opening the valved outlet and causing the medication particles to be conveyed from the valved outlet through the receptacle component and discharged from an outlet of the receptacle component. Upon discharge from the canister, the medication particles are xe2x80x9catomizedxe2x80x9d forming an aerosol. It is intended that the patient coordinate the discharge of aerosolized medication with his or her inhalation so that the medication particles are entrained in the patient""s inspiratory flow and conveyed to the lungs. Typically, pMDls have used propellants, such as chlorofluorocarbons (CFCs), to pressurize the contents of the canister and to propel the medication particles out of the outlet of the receptacle component.
Although conventional pMDIs have been widely used to provide many patients with the benefits of aerosol medication, conventional pMDIs have certain drawbacks. For example, an objective of aerosol therapy has been the optimization of the mass percentage of the respirable dose of an aerosol medication in order to optimize deposition in a patient""s lungs to achieve a full therapeutic effect with the least possible side-effects. Conventional pMDIs may not have always been able to meet this objective.
One drawback associated with conventional pMDIs relates to the discharge velocity of the aerosol particles. Medication particles are stored under considerable pressure in the pMDI canister and as a consequence, their velocity may be high upon discharge.
Among other things, the effect of high velocity contributes to a significant number of aerosol medication particles impacting and depositing in the patient""s oropharynx and upper airway rather than continuing their pathway through the upper airway and into the lungs. Such impaction and deposition may result in a significant portion of the medication dose being systemically absorbed or ingested. As documented in the literature [J. L. Rau, xe2x80x9cRespiratory Care Pharmacologyxe2x80x9d, 4th ed. (1994, Mosby) at pp. 256-261; K. Meeran, A. Hattersley, J. Burrin, R. Shiner, K. Ibbertson K., xe2x80x9cOral and Inhaled Corticosteroids Reduce Bone Formation as Shown by Plasma Osteocalcin Levelsxe2x80x9d, Am. J. Respir. Crit. Care Med 151:333-336], systemic absorption or ingestion of aerosol medication may cause a patient adverse side-effects, particularly when the aerosol medication is a corticosteroid. Some of these adverse side-effects include pharyngeal candidiasis, hoarseness, and adrenal suppression.
The high velocity of the aerosol medication particles may also accentuate the difficulty of a significant number of patients, particularly the very young and elderly, to coordinate actuation of the pMDI with inhalation of the aerosol medication particles generated. Failure to coordinate the actuation and inhalation maneuvers and failure to inhale slowly, have been documented by the literature [S. P. Newman, xe2x80x9cAerosol Deposition Considerations in Inhalation Therapyxe2x80x9d Chest/88/2/August, 1985/Supplement] as contributing to a significant reduction in the number of aerosol medication particles inspired and deposited in a patient""s lungs.
Impaction and deposition of aerosol medication particles on a patient""s oropharynx and upper airway may also contribute to an unpleasant taste in a patient""s mouth, particularly with certain medication solution or suspension formulations such as flunisolide.
In addition to high particle velocity, a significant number of large non-respirable medication particles may be produced upon discharge as a result of the medication suspension or solution formulation as well as the atomization process. As mentioned above, conventional pMDIs have used CFCs to propel the medication out of the pMDI actuator outlet. In view of environmental concerns with CFCs, there has been a growing interest in using non-CFC propellants, such as hydrofluoroalkanes (HFAs).
An inhalation valve is often used in conjunction with an aerosol medication delivery apparatus to deliver a medication in an aerosol form to a user""s respiratory tract. Typically, an inhalation valve is disposed at the output end of an aerosolization chamber and prevents aerosolized medication from leaving the chamber when the inhalation valve is in a closed position. When a patient inhales, the inhalation valve opens and allows the aerosolized medication to enter the patient""s respiratory tract. The inhalation valve is usually designed to close upon exhalation by the patient.
Prior art inhalation valves generally consist of a valve member and a valve seat. In some types of prior art valves, the outer perimeter of the valve member seals against the valve seat. In operation, the act of inhalation causes the outer perimeter of the valve to move away from the valve seat and allow aerosolized medication to flow through to the patient.
In another type of prior art inhalation valve, the valve member includes one or more slits that define flaps on the valve member. Typically, the valve seat has a plurality of openings defined by what is known as a spider-like framework. In operation, when the patient inhales the flaps move away from the spider-like framework to allow aerosolized medication to pass through the openings to the patient. Upon exhalation, the flaps move against the framework to cover the openings. A number of advantageous improvements and modifications can be made to these prior designs.
It is another object to provide a device which reduces the need for a patient to coordinate activation of a pMDI canister with inhalation.
It is a further object to provide a device that reduces the delivery of non-respirable medication particles from a pMDI canister to a patient.
It is yet another object to provide a device that reduces the impaction of medication particles on a patient""s oropharynx and upper airway.
It is still another object to provide a device for the delivery of aerosol medication from a pMDI canister that uses an HFA propellant instead of a CFC propellant.
In order to address the above noted objectives, as well as other objectives, the present invention provides an improved aerosol medication delivery apparatus. The aerosol medication delivery apparatus includes a canister-holding portion and a chamber housing. The canister-holding portion has a receptacle for receipt of a pMDI canister containing a medication and a propellant. The canister-holding portion has a discharge orifice communicating with the receptacle to direct an aerosol into an interior of the chamber housing at an input end thereof. The chamber housing also has an output end from which medication can be withdrawn by inhalation by a patient. The canister-holding portion and the chamber housing are coupled together by a mechanism that provides for the canister-holding portion to be retracted into the chamber housing for storage. The coupling mechanism also allows the canister-holding portion to be extracted from its storage position in the chamber housing and pivoted into position for use when dispensing medication. According to one aspect of the present invention, the aerosol delivery system includes a containment baffle located at the output end of the chamber housing to partially block the output end.
Further in this aspect the containment baffle may be surrounded by an inhalation area including at least one opening and wherein the inhalation area is located concentrically with the containment baffle and the containment baffle is aligned with the discharge orifice. There may also be provided a backpiece located on the input end of the chamber housing, the backpiece including an opening located therein to receive a mouthpiece of an actuator boot of the pMDI canister. Also in this aspect the containment baffle may define an inhalation opening area located around a periphery thereof wherein the inhalation opening area has four arcuate-shaped openings, the containment baffle may be located at an upstream end of a mouthpiece extending from the output end of the chamber housing portion, the containment baffle may be located at a downstream end of a mouthpiece extending from the output end of the chamber housing portion. There may also be provided a receptacle coupled to the chamber housing at an upstream portion thereof; a well located in a bottom of the receptacle, the well communicating with the discharge orifice; and further wherein the chamber housing portion includes a first opening at the input end coupled to a ventilator circuit and a second opening at the output end leading to the patient. Further, the receptacle and chamber housing may be formed of an integrated unit.
According to another aspect, the aerosol medication delivery apparatus includes a canister-holding portion and a chamber housing. The canister-holding portion has a receptacle for receipt of a pMDI canister containing a medication and a propellant. The canister-holding portion has a discharge orifice communicating with the receptacle to direct an aerosol into an interior of the chamber housing at an input end thereof The chamber housing also has an output end from which medication can be withdrawn by inhalation by a patient. The canister-holding portion and the chamber housing are coupled together by a mechanism that provides for the canister-holding portion to be retracted into the chamber housing for storage. The coupling mechanism also allows the canister-holding portion to be extracted from its storage position in the chamber housing and pivoted into position for use when dispensing medication. According to one aspect of the present invention, the aerosol delivery system includes a containment baffle located at the output end of the chamber housing to partially block the output end.
Further, in this aspect the containment baffle may be concave-like in shape as viewed from the interior space, the containment baffle may include at least one opening located concentrically adjacent thereto and the containment baffle may be aligned with the discharge orifice. Further in this aspect, there may be provided a pMDI canister of medication having a stem, wherein the canister is located at least in part within the receptacle. Also the canister may contain HFA, the medication may include flunisolide, the containment baffle may be convex-like in shape as viewed from the interior space, the chamber housing may have squared-off sides, the containment baffle may define an inhalation opening area located around a periphery thereof, the inhalation opening area may have four arcuate-shaped openings. In this aspect the containment baffle may have a solid center portion located along a central axis of the chamber housing, the containment baffle may have a center portion having a plurality of openings formed through a periphery thereof, the containment baffle may have a screen-like mesh defining a plurality of openings therethrough. Also in this aspect, the ambient air can pass into the interior space when a pMDI canister is located in the canister-holding portion, the containment baffle may have a curved top and bottom sides and straight vertical sides, the containment baffle may include a center portion coupled to the chamber housing by a plurality of ribs, the containment baffle may be located at an upstream end of a mouthpiece extending from the output end of the chamber housing portion, the containment baffle may be located at a downstream end of a mouthpiece extending from the output end of the chamber housing portion. Further in this aspect there may be provided a mechanism coupling the canister holding portion and the chamber housing providing for the canister-holding portion to be retracted into the chamber housing for storage and to be extended out of the chamber housing and pivoted into position for use in dispensing medication.
In another aspect, an aerosol medication delivery apparatus includes a canister-holding portion including a receptacle for receipt therein of a pMDI canister, wherein the pMDI canister has medication and a propellant contained therein under pressure, the canister-holding portion having a discharge orifice communicating with the receptacle to receive the medication and propellant from the pMDI canister; a chamber housing having an input end and an output end from which medication can be withdrawn by a patient, the chamber housing defining an interior space wherein the discharge orifice of the canister-holding portion communicates with the interior space at the input end, a mechanism coupling the canister-holding portion and the chamber housing providing for the canister-holding portion to be retracted into the chamber housing for storage and to be extended out of the chamber housing and pivoted into position for use in dispensing medication; and a containment baffle located at the output end to partially block the open output end.
In addition, in this aspect the containment baffle may be concave-like in shape as viewed from the interior space. Further, in this aspect containment baffle may include at least one inhalation opening area located concentrically adjacent thereto, the containment baffle may be axially aligned with the discharge orifice. This aspect may provide a pMDI canister of medication having a stem, wherein the canister is located at least in part within the receptacle, the canister may contain HFA and the medication may include flunisolide. Also in this aspect the containment baffle may define an inhalation opening area located around a periphery thereof, the inhalation opening area may include four arcuate-shaped openings, the containment baffle may include a solid center portion located along a central axis of the chamber housing. In addition, in this aspect ambient air may pass into the interior space when a pMDI canister is located in the canister-holding portion, the containment baffle may have a curved top and bottom sides and straight vertical sides and the containment baffle may be located at a downstream end of a mouthpiece extending from the output end of the chamber housing portion.
In another aspect, an aerosol medication delivery apparatus includes a chamber housing with an input end an output end. The input end receives the discharge of a medication from a pMDI canister and the output end includes a containment baffle that partially blocks the output end. The pMDI canister is received in an elastomeric backpiece that is adapted to accommodate various sizes of actuator boot mouthpieces.
In another aspect, the invention provides an aerosol medication delivery apparatus for use with a pMDI canister having medication and a propellant contained therein under pressure, wherein the pMDI canister has a discharge orifice from which the medication and propellant can be discharged forming an aerosol. The apparatus has a chamber housing having an input end and an output end and defining an interior space, wherein the input end receives the medication discharged from the discharge orifice of the pMDI canister into the interior space and wherein the medication can be withdrawn from the interior space by inhalation by a patient from the output end. The aerosol medication delivery apparatus also includes a valve at the output end. The valve has a valve seat and a valve member. The valve seat has a sealing surface and the valve member has a central open area and a sealing portion at the perimeter of the central open area that mates with the sealing surface when the valve is closed. The valve allows medication to be withdrawn through the central open area but prevents backflow into the chamber housing.
This aspect of the present invention may also be provided with a containment baffle located at the output end. Also the sealing surface may be formed on the outer perimeter of the containment baffle, the containment baffle may be dome shaped and include a concave surface and a convex surface, wherein the convex surface faces downstream and the concave surface faces toward the input end of the chamber. This aspect of the invention may further be provided with a retainer defining a channel near the output end, an engaging member located on the valve member, wherein the engaging member is movable between a first position and a second position within the channel. In addition, the convex surface may face toward the input end of the chamber housing, the central open area may be circular shaped, the valve member may have an inner portion, an outer portion and an engaging member, inhalation openings are located near the output end and are defined between the containment baffle and the chamber housing. This aspect of the invention may further be provided with a protrusion formed near the output end on the outer surface of the chamber housing. Also, in this aspect the inner portion may be positioned adjacent the inhalation openings; the engagement member may concentrically surround the protrusion, the valve member may be dome shaped in cross section, the apparatus may also include a downstream portion attached with the output end wherein the downstream portion has an inner surface and a plurality of retaining ribs spaced apart from the inner surface. The retaining ribs define gaps which permit exhaled air to flow through to the atmosphere. The present invention may further be provided with a valve member that is made of a rigid material and the sealing portion may form a continuous surface.
In another aspect, the invention provides an aerosol medication delivery apparatus for use with a pMDI canister having medication and a propellant contained therein under pressure, wherein the pMDI canister has a discharge orifice from which the medication and propellant can be discharged forming an aerosol. The apparatus has a chamber housing having an input end and an output end and defining an interior space, wherein the input end receives the medication discharged from the discharge orifice of the pMDI canister into the interior space and wherein the medication can be withdrawn from the interior space by inhalation by a patient from the output end. The apparatus includes a mouthpiece operatively attached to the output end; and a valve located near the output end having a valve seat having a sealing surface and a valve member having an inner portion and an outer portion. The inner portion has a central open area and a sealing portion at the perimeter of the central open area that mates with the sealing surface when the valve is closed, wherein the inner portion allows medication to be withdrawn through the central opening but prevents backflow into the chamber housing. The outer portion is located in a peripheral opening defined between the chamber housing and the mouthpiece, the outer portion operates to prevent air flow through the peripheral opening upon patient inhalation but which permits air flow through the peripheral opening upon exhalation into the mouthpiece.
Further, in this aspect of the invention there may be provided a containment baffle located at the output end to partially block the output end and the sealing surface may be located at the periphery of the containment baffle.
In another aspect, the invention provides an aerosol medication delivery apparatus for use with a pMDI canister having medication and a propellant contained therein under pressure, wherein the pMDI canister has a discharge orifice from which the medication and propellant can be discharged forming an aerosol. The apparatus has a chamber housing having an input end and an output end and defining an interior space, wherein the input end receives the medication discharged from the discharge orifice of the pMDI canister into the interior space and wherein the medication can be withdrawn from the interior space by inhalation by a patient from the output end. The aerosol medication delivery apparatus also includes a valve at the output end. The valve has a valve seat and a valve member. The valve seat has a sealing surface and the valve member has a central open area and a sealing portion at the perimeter of the central open area that mates with the sealing surface when the valve is closed. An engagement member is located on the valve member. The valve allows medication to be withdrawn through the central open area but prevents backflow into the chamber housing.
Further in this aspect of the invention the valve member may have an inner portion, the engagement member may include an input side and an output side, a downstream portion may be attached to the output end, a mouthpiece may be attached to the downstream portion, an inner surface of the downstream portion may define a recess, the output side of the engagement member may be disposed in the recess, the central open area may be circular shaped, the diameter of the chamber housing gradually increases from the input end to the output end, a baffle member may be attached to the output end, a receiving member may be formed on a downstream end of the baffle member, the input side of the engaging member may be concentrically disposed around the receiving member, a mask may be attached to the output end. Further in this aspect, the sealing portion may form a continuous surface.
In another aspect, the invention provides a method for delivering aerosol medication to a patient including the following steps: providing a pMDI canister having medication and a propellant contained therein under pressure, wherein the pMDI canister has a discharge orifice; providing a chamber housing having an input end and an output end and defining an interior space, wherein the input end receives the medication discharged from the orifice of the pMDI canister into the interior space and wherein the medication can be withdrawn from the interior space by inhalation by a patient from the output end; providing a valve at the output end including a valve seat and a valve member, the valve seat having a sealing surface and the valve member having a central open area and a sealing portion at the perimeter of the central open area; depressing the pMDI canister; discharging medication and propellant out from the discharge orifice; forming an aerosolized medication; passing aerosolized medication through the chamber housing and to the patient.
In another aspect the invention provides an aerosol medication delivery apparatus for use with a pMDI canister having medication and a propellant contained therein under pressure, wherein the pMDI canister has a discharge orifice from which the medication and propellant can be discharged forming an aerosol, the apparatus includes a chamber housing having an input end and an output end and defining an interior space, wherein the input end receives the medication discharged from the discharge orifice of the pMDI canister into the interior space and wherein the medication can be withdrawn from the interior space by inhalation by a patient from the output end; means for sealing the chamber housing having a base and a movable member movable between an open position and a closed position, the movable member having a central open area. The means for sealing the chamber housing allows medication to be withdrawn through said central open area when the movable member is in the open position but prevents backflow into the chamber housing when the movable member is in the closed position.
The invention provides the foregoing and other features, and the advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention and do not limit the scope of the invention, which is defined by the appended claims and equivalents thereof.